San Diego State University competitive swimmers:
In the course of preparing materials for the Swimming Science Journal, I came across the following articles concerning chlorinated pools.

WHAT IS KNOWN

1. Exercising competitive swimmers absorb toxic levels of chlorine products in the course of a training session.
2. Training two or more times a day will not allow the toxins to be completely cleared from the body in most swimmers.
3. Children inhale more air per unit of body weight than mature persons, and have lesser developed immune and defense systems.
4. Young children absorb relatively greater amounts of toxins than older swimmers and therefore, are at greater risk.
5. In hyper-chlorinated pools, even dental enamel can be eroded because of the increased acidity in swimmers in training.
6. Exercise intensity and number of sessions increase the toxic concentrations in competitive swimmers.
7. Greater toxin absorption occurs through the skin than through breathing. However, the breathing action alone is sufficient to cause hypersensitivity and “asthma-like” respiratory conditions in at least some swimmers. The percentage of asthma-like symptoms in swimmers that is attributable to exposure to chlorinated hydrocarbons versus being unrelated to chlorine exposure is presently unknown. This is an area clearly deserving of further research.
8. Overchlorination is particularly hazardous to the health of swimmers.
9. Exposure to swimming pool water increases the likelihood of some cancers.